The production of container packages for liquid contents such as milk, juice or the like is normally carried out starting with blanks or webs of flexible packaging laminate. The laminate, which comprises layers of paper, thermoplastic and possibly aluminium foil, is divided, by means of crease lines, into different panels which, after folding and sealing of the material, form the different walls of the finished package or carton.
In the production of one well-known type of package, the so-called gable-top carton, the bottom is formed by means of a number of bottom panels which are folded and heat-sealed together in order to form a planar, liquid-tight bottom in the package. In the ready-folded state, the bottom construction includes, among other items, two substantially triangular bottom panels which are disposed interiorly in the package and have pointed corners directed towards one another at the central region of the bottom. In such package, it has been found that during transport, stacking or other handling of the packages these corners show a tendency to partially penetrate subjacent bottom panels in the package so that the interior thermoplastic sealing layer of these bottom panels is damaged and leakage occurs. While such leakage is not normally so serious that the contents held in the package run out, the contents may on occasion be absorbed into the subjacent layer of the packaging material so that this layer becomes soggy, discoloured and its mechanical strength becomes impaired.
Attempts have hitherto been made in the art to avoid the above-outlined problem by providing the bottom of the package with a different folding pattern, which may wholly obviate the aforementioned problem, since the interiorly located pointed corners may be dispensed with. However, this necessitates a total redesign of not only the crease line pattern and the tools which are employed for forming the crease lines, but also of those parts of the packaging machine which--in a predetermined sequence and according to predetermined movements--fold in and seal the different laminate panels which together form the bottom of the package. Moreover, it has been found in practice that the conventional bottom folding pattern offers so many advantages (in the form of simpler folding, more even bottom and, normally, also greater liquid-tightness) that this bottom design is preferred notwithstanding its drawbacks.